BRUSSELS, July 12 (Reuters) - The European Union targeted Ukrainian separatist leader Aleksandr Borodai and 10 other rebels with travel bans and asset freezes on Saturday, avoiding fresh sanctions on Russian business to avoid antagonising its main energy supplier.

EU governments widened their blacklist to try to end the violence that has rocked Ukraine since late last year, when a decision by the then president to reject an EU trade deal sparked fatal protests and forced him to flee the country.

The European Union said Borodai was "responsible for the separatist 'governmental' activities of the so-called 'government of the Donetsk People's Republic'," referring to the city where the military is fighting pro-Russian separatists.

Borodai, a 41-year-old Russian citizen, told a news conference in May that he was a political advisor who helped Russia's annexation of the Ukrainian peninsula Crimea in March and then moved to eastern Ukraine to help separatists there.

He denies any links to Moscow.

Others on the EU list include Alexander Khodakovsky, a defector from the Ukrainian state security service who now commands rebels, and Nikolay Kozitsyn, identified by the EU as another rebel commander.

Kiev denounces them as terrorists and accuses Russia of supporting the rebellion in the east, where hundreds of people have died in the clashes between rebels and the military.

SANCTIONS CONDEMNED

When the sanctions were announced last week, Russia condemned them and said it would damage ties with Europe.

The EU's trade chief, Karel De Gucht, held talks with Russian and Ukrainian officials in Brussels on Friday and sought to reassure Moscow it was not seeking to hurt the Russian economy. But EU officials rejected calls to delay the free-trade and political cooperation accord that the EU finally signed with Ukraine last month.

The list takes the number of people under EU sanctions to 72, as well as two energy companies in Crimea, taken over by Moscow earlier this year.

EU leaders warned at a June 27 summit that the bloc could impose more sanctions on Moscow unless pro-Russian rebels wound down the crisis in the east of the country.

The EU has hesitated about imposing hard-hitting trade sanctions against Russia because of fears among some countries such as Germany about antagonizing their major energy supplier.

Poroshenko called off a patchy ceasefire to resume an offensive against pro-Moscow rebels in eastern Ukraine.

Ukraine scrambled jet fighters to strike at rebel positions early on Saturday, after separatists resumed missile attacks on government forces near the frontier with Russia, the border guard service said.

In a night of violence in several areas of eastern Ukraine following a missile strike by separatists on Friday that killed at least 23 government servicemen, Ukrainian forces also used artillery to respond to rebel fire, the military said.

Poroshenko had pledged to "find and destroy" the pro-Russian rebels responsible for the missile attack at Zelenopillya, which also injured nearly 100. (Reporting by Robin Emmott; Editing by Lynne O'Donnell)